In general, a dryer is a machine for drying laundry by introducing the laundry, after washing, to a drum, or tub, for spinning while supplying heated air to inside the drum to evaporate moisture from the laundry.
The air discharged to an outside of the drum from the inside of the drum, after exchanging heat with and absorbing moisture from the laundry, attains higher humidity and temperature. Dryers may be classified according to the system used for treating the humid and high temperature air. For example, the dryer may be an exhaust type dryer that discharges the humid and high temperature air from the drum to an outside of the dryer. Additionally, the dryer may be a condensing type dryer in which a heat exchanger condenses and heats the air from the drum, and in which the humid and high temperature air is re-supplied to the drum (i.e., the air from the drum is circulated).
The air being discharged from the drum during drying may contain foreign substances, such as lint or the like, coming from the object being dried, such as clothes. The foreign substance can harm the dryer if passed through mechanical elements of the dryer, and can also pollute outdoor air if discharged to an outside of the dryer. Therefore, the dryer is required to remove the foreign substance from the air being discharged from the drum.
In general, a filter provided to the dryer is positioned on a front of the drum for filtering the foreign substance from the air discharged from the drum. Accordingly, if the dryer is used continuously, the filter may accumulate the foreign substance, such as lint, thereon.
If the accumulation of the foreign substance on the filter becomes greater than a preset level, the foreign substance can interfere with the discharge of the air from the drum; thus, the filter in the dryer should be cleaned periodically. The filter cleaning is carried out as the user separates the filter from the dryer after finishing a drying cycle, removes the foreign substance from the filter, and again mounts the filter to the dryer.
However, such filter cleaning carried out manually is not only cumbersome but also, because the filter cleaning may not be carried out every time the dryer is operated, can lead to, until the filter is cleaned, a failure to secure adequate air flow rate required for drying due to the foreign substance interfering with the air flow being discharged from the drum.